Distribution. It is reported that purslane was a common vegetable of the Roman Empire. Origin of purslane is not certain, but existence of this plant is reported about 4,000 years ago. The succulent stems and fleshy leaves of purslane reflect that it may have originated and adapted to desert climates of the Middle East and India. It can be found in Europe, Africa, North America, Australia, and Asia.
Botanical Classification. Portulaca oleracea is s cosmopolitan species and the genus Portulaca belongs to the family Portulacaceae, a small family with 21 genera and 580 species, and is cosmopolitan in distribution, occurring especially in America with some species found in Arabia. Purslane plants are succulent, annual herbaceous, and erect or decumbent up to 30 cm high. Purslane is botanically known as Portulaca oleracea and is also called portulaca.
Habitat. It grows well in orchards, vineyards, crop fields, landscaped areas, gardens, roadsides, and other disturbed sites.
Leaf. Purslane leaves are alternate or subopposite, flat, fleshy, having variable shapes, obovate, 1–5 cm long, 0.5–2 cm across, obtuse or slightly notched at the apex, tapering at base, sessile or indistinctly petiolate, glabrous, smooth, and waxy on the upper surface, with entire margin, small stipules, and cluster of hairs up to 1 mm long. Leaves are egg to spatula shaped, succulent, and stalkless or have very short stalks, about 5–30 mm long, and sometimes their edges are redtinged. Leaves are green or green with red margin.
Seedling. Cotyledons (seed leaves) are egg shaped to oblong, hairless, succulent, about 2–5 mm long, and sometimes tinged red.
Flower. Flowering initiates during May to September. Flowers originate as single or clusters of two to five at the tips of stems. The flowers are minute or small having orange yellow, purple, or white pink color with five petals and typically open only on hot and sunny days from mid-morning to early afternoon.
Fruit. Fruit consists of almost round to egg-shaped capsules, usually about 4–8 mm long that open around the middle to release the seeds. Seeds are tiny, less than 1 mm in diameter, circular to egg shaped, flattened, and brown to black with a white point of attachment. Numerous seeds are produced.
2.1. Nutrition. It is rich in vitamin A which is a natural antioxidant value. It can play role in vision healthy mucus membranes and to protect from lung and oral cavity cancer. Purslane contains the highest content of vitamin A among green leafy vegetables. It also contains vitamin C and Bcomplex vitamins like riboflavin, niacin, and pyridoxine. It provides highest dietary minerals such as potassium (494 mg/100 g) followed by magnesium (68 mg/100 g), calcium (65 mg/100 g), phosphorus (44 mg/100 g), and iron (1.99 mg/100 g). The range of Ca, Mg, K, Fe, and Zn from the young stage to mature plants was from 1612 ± 27 to 1945 ± 30 mmol kg−1 DW, 2127 ± 23 to 2443 ± 27 mmol kg−1 DW, 1257 ± 10 to 1526 ± 31 mmol kg−1 DW, 218 ± 8 to 262 ± 3 mmol kg−1 DW, and 128 ± 2 to 160 ± 1 mmol kg−1 DW, respectively. On the other hand, the Na and Cl concentrations in leaves were higher at the young stage and lower at the mature stage. The Na and Cl concentrations ranged from 356 ± 4 to 278 ± 8 mmol kg−1 DW and from 82 ± 2 to 53 ± 2 mmol kg−1 DW, respectively.
2.2. Omega-3 Fatty Acid. Purslane is one of the richest green plant sources of omega-3 fatty acids. It has lower the cholesterol and triglyceride levels, raise the beneficial high-density lipoprotein. Moreover, the ability of omega-3 fatty acids to decrease the thickness of the blood may be advantageous in the treatment of vascular diseases. Unlike fish oils with their high cholesterol and calorie content, purslane also provides an excellent source of the beneficial omega-3 fatty acids without the cholesterol of fish oils, since it contains no cholesterol. There are 3 varieties of purslane, namely, the green, golden, and a large-leaved golden variety. Important sources of omega-3 fatty acids are summarized in Table 2. It has a low incidence of cancer and heart disease, possibly due in part to purslane’s naturally occurring omega 3 fatty acids.